Our solution is to use monit to auto-remount the s3fs directory if it dies. In this example, it is the wordpress uploads folder we are monitoring as it's used to share files between two load balanced servers (not the best solution, but it works).

1.Install monit:

# apt-get install monit

2.Enable shell access to monit by editing /etc/monit/monitrc and uncommenting the following:

set httpd port 2812 and
use address localhost # only accept connection from localhost
allow localhost

Check file s3fs with path /home/user/public_html/wp-content/uploads/monit-test-dont-delete.txt
start program = "/etc/monit/scripts/start-s3fs.sh"
stop program = "/etc/monit/scripts/stop-s3fs.sh"
if does not exist then restart
if 5 restarts WITHIN 5 cycles then timeout

/home/user/public_html/wp-content/uploads/monit-test-dont-delete.txt:

monit test file, don't delete

5.Now you can restart monit, manually run /etc/monit/scripts/stop-s3fs.sh to trigger a stop, watch mount and /var/log/monit.log to ensure your monit service detects the directory being unmounted and ensure your script is run to remount it.